反应详情

A 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer and nitrogen inlet was purged with nitrogen and charged with 120a (1.14 g, 2.62 mmol), methylene chloride (10 mL) and trifluoroacetic acid (10 mL). The solution was stirred for 2 h at room temperature. After this time, the solution was concentrated under reduced pressure. The residue was partitioned between methylene chloride (100 mL) and 1 M aqueous dibasic potassium phosphate (30 mL). The aqueous layer was extracted with a 20% (v/v) solution of methanol in methylene chloride (3×100 mL). The organic extracts were combined, washed with brine (20 mL) and dried over sodium sulfate. The drying agent was removed by filtration, and the filtrate was concentrated under reduced pressure to afford a 68% yield (600 mg) of 153a as an off-white solid: mp 170-171° C.; 1H NMR (300 MHz, DMSO-d6) d 9.30 (s, 1H), 7.62 (m, 2H), 7.31 (s, 1H), 6.97 (d, 1H, J=7.8 Hz), 4.10 (br s, 1H), 3.83 (s, 2H), 3.43 (s, 3H), 2.96 (t, 2H, J=5.7 Hz), 2.68 (t, 2H, J=5.7 Hz); MS (ESI+) m/z 334.0 (M+H).

1. customA 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer and nitrogen inlet
2. customwas purged with nitrogen
3. concentrationAfter this time, the solution was concentrated under reduced pressure
4. customThe residue was partitioned between methylene chloride (100 mL) and 1 M aqueous dibasic potassium phosphate (30 mL)
5. extractionThe aqueous layer was extracted with a 20% (v/v) solution of methanol in methylene chloride (3×100 mL)
6. washwashed with brine (20 mL)
7. dry with materialdried over sodium sulfate
8. customThe drying agent was removed by filtration
9. concentrationthe filtrate was concentrated under reduced pressure